Java 从 ZipInputStream 条目创建 InputStream [英] Java create InputStream from ZipInputStream entry

问题描述

我想编写一个方法，从单个 InputStream 读取 ZIP 中的多个 XML 文件.

I would like to write a method that read several XML files inside a ZIP, from a single InputStream.

该方法将打开一个 ZipInputStream，并在每个 xml 文件上获取相应的 InputStream，并将其提供给我的 XML 解析器.这是该方法的骨架:

The method would open a ZipInputStream, and on each xml file, get the corresponding InputStream, and give it to my XML parser. Here is the skeleton of the method :

private void readZip(InputStream is) throws IOException {

    ZipInputStream zis = new ZipInputStream(is);
    ZipEntry entry = zis.getNextEntry();

    while (entry != null) {

        if (entry.getName().endsWith(".xml")) {

            // READ THE STREAM
        }
        entry = zis.getNextEntry();
    }
}

有问题的部分是//READ THE STREAM".我有一个可行的解决方案，它包括创建一个 ByteArrayInputStream，并将它提供给我的解析器.但它使用缓冲区，对于大文件，我得到一个 OutOfMemoryError.这是代码，如果有人仍然感兴趣:

The problematic part is the "// READ THE STREAM". I have a working solution, which consist to create a ByteArrayInputStream, and feed my parser with it. But it uses a buffer, and for large files I get an OutOfMemoryError. Here is the code, if someone is still interested :

int count;
byte buffer[] = new byte[2048];
ByteArrayOutputStream out = new ByteArrayOutputStream();
while ((count = zis.read(buffer)) != -1) { out.write(buffer, 0, count); }       
InputStream is = new ByteArrayInputStream(out.toByteArray());

理想的解决方案是将原始 ZipInputStream 提供给解析器.它应该可以工作，因为如果我只是使用扫描仪打印条目内容，它就可以工作:

The ideal solution would be to feed the parser with the original ZipInputStream. It should works, because it works if I just print the entry content with a Scanner :

Scanner sc = new Scanner(zis);
while (sc.hasNextLine())
{
    System.out.println(sc.nextLine());
}

但是...我目前使用的解析器(jdom2，但我也尝试使用 javax.xml.parsers.DocumentBuilderFactory)在解析数据后关闭流:/.所以我无法获得下一个条目并继续.

But... The parser I'm currently using (jdom2, but I also tried with javax.xml.parsers.DocumentBuilderFactory) closes the stream after parsing the data :/ . So I'm unable to get the next entry and continue.

所以最后的问题是:

• 有人知道不关闭流的 DOM 解析器吗?
• 还有其他方法可以从 ZipEntry 获得 InputStream 吗?

谢谢.

推荐答案

您可以包装 ZipInputStream 并拦截对 close() 的调用.

You could wrap the ZipInputStream and intercept the call to close().

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